1. Field of the Invention
The present invention relates to a disk-type medium, such as an optical disk and a magneto-optical disk, and, more particularly, to a disk case that can exchangeably accommodate a disk in which the recording of information is enabled.
2. Description of the Related Art
To date, as a disk-type recording medium, for example, a write once or rewritable optical disk is being used. When this type of disk is mounted on or dismounted from a recorder and/or a disk reproducing apparatus (hereinafter referred to as a drive) in the bare disk (disk itself) state, there was a fear that a hand and a finger touches the disk and fingerprints are stuck to the disk, thereby staining the signal recording side. Further, to prevent them, the disk might also be accommodated and used in a cartridge main body having a shutter that opens and closes an opening. In a cartridge system, because the shutter usually closes except when a disk is mounted on a drive, the disk is disconnected from the outside world. Accordingly, the cartridge system is excellent in preventing the disk surface from the dirt caused by dust and fingerprints.
In recent years, instead of a conventional magnetic tape, a camera that uses a disk having excellent accessibility as a recording medium has also started appearing. More downsizing or weight reduction is desired as a camera from the handleability or operability in the same manner as the camera that uses the magnetic tape.
Further, in view of the operating environment of a camera, because the camera is frequently used outdoors, it is desirable that a disk should be used in a form close to the cartridge system in which dust and fingerprints are difficult to stick instead of being used as a bare disk as much as possible.
Next, the prevention of incorrect insertion of a cartridge into a drive is described. Here, the case where an 8-cm DVD-RAM cartridge is used as an example is described with reference to FIGS. 9 and 10.
FIG. 9 is a top plan view when a conventional disk cartridge is inserted correctly into a loader, and FIG. 10 is a top plan view when the conventional disk cartridge is inserted into the loader from the incorrect direction.
The prevention of incorrect insertion is a necessary invention for enabling mounting of a cartridge on a drive only from the specified direction of the cartridge and securely exchanging a signal on a disk in the cartridge opening.
In FIGS. 9 and 10, 1 indicates a disk (shown by a dotted line), 22 indicates a cartridge, and 22c indicates a cartridge main body. An opening 22a is provided in the cartridge main body 22c. 25 is a shutter. 22i is a straight portion at the side of the cartridge main body 22c. The shutter 25 is mounted on the cartridge main body 22c in a slide system. 30 is a loader of the cartridge at the drive side.
Here, the axis that connects the cartridge opening width center from the center O of the disk 1 is a Y-axis and the axis that passes through the center O of the disk 1 and is vertical to the Y-axis is an X-axis. Further, when it is assumed that the length in the Y-axis direction of the cartridge is L0, the length in the X-axis, that is, the width is W0, and the width of the loader 30 is D, the relationship is specified in the specifications so as to satisfy L0>W0, and, moreover the width of the loader is designed to satisfy L0>D>W0.
FIG. 9 shows a state in which the cartridge 22 is mounted in the correct direction, that is, in the Y-axis direction (direction of an arrow E in FIG. 9) to the loader 30. In this case, the cartridge 22 moves in a way in which the straight portion 22i of the cartridge main body 22c is guided to the loader 30. When the cartridge 22 moves to the inside of the loader 30 at a predetermined distance, the shutter 25 slides and opens by a switching apparatus that is not shown and can securely exchange a signal using the disk 1 with the drive side (not shown) via the opening 22a. 
On the contrary, FIG. 10 shows the case where a user is attempting to mount the cartridge 22 in the incorrect orientation to the loader 30.
As described previously, because the cartridge length L0, the width W0, and the width D of the loader 30 have a relationship of L0>D>W0, the cartridge 22 will not be inserted into the loader 30 even if the cartridge 22 is mounted in the X-axis direction (direction of the arrow E in FIG. 10) to the loader 30. Accordingly, the erroneous operation of the drive caused by the incorrect insertion of the cartridge can be prevented in advance.